14.4 Japan Earthquake- AC Case Study

Question 1

What are the general facts of the earthquake?

Answer 1

Country: Japan
Development classification: AC
Date of earthquake: 11/03/11, 11:56am

Question 2

What are the geophysical facts of the earthquake?

Answer 2

Magnitude: 9.0
Epicentre: 30km below pacific seabed
The earthquake resulted from thrust faulting on the subduction zone.
Aftershocks:
The main quake was followed by over 5000 aftershocks, including one with a magnitude of 7.9.

Question 3

What are other general place and/or earthquake information?

Answer 3

• Japans east coast has lurched 4 metres out to the pacific and sunk by over a metre.
• 7.2 magnitude foreshock two days before the earthquake struck.
  
  • This foreshock shed stress around the area as additional stress- covering the area of the main shock. This was thought to provoke the main shock.
• Final tsunami waves stopped 3.5 hours after the earthquake.

Question 4

What were the social impacts?

Answer 4

• The Japanes earthquake was on a scale that noone had anticipated or rehearsed for:
  
  • out of the ordinary.
• Japan prepared and had good education however not for this magnitude.
• Tsunami warnings are issued immediately, however as they are often sounded people can be subject to complacency.
  
  • Has become too normal and they fell into a false sense of security- not the whole population, only a small number of.
• 16000 people dies and 6000 people injured.
• 2/3 of victims were over 60, 1/4 were over 70.
  
  • 90% of deaths due to drowning, others were from burns or collapsing buildings
• Traditional funeral traditions were ignored- bodies were buried in mass graves to reduce the chances of disease transmission.
• Children were seperated from their families:
  
  • Save the Children reported 100,000 children were impacted- made worse by the fact that many were at school when it happened.
  • One of the coastal schools lost 74 of 108 students and 10 of 13 staff.
• The destruction of infrastructure was on such a large scale that reconstruction was ongoing 5 years after the disaster- some communities will have been relocated from their original settlement site.

Question 5

What were the economic impacts?

Answer 5

• A lot infrastructure lost- houses, vehicles and agricultural impacts.
• The cost of the earthquake was nearly £181 billion.
• Japans National Policy Agency issued an official figure of 45,700 buildings destroyed, 143,300 damaged, 230,000 vehicles destroyed or damaged, 15 ports impacted (4 in the North East eg, Sendai) and 10% of fishing ports were damaged- many reopened a year later.
• Disruption of power supplies (arguably most important):
  
  • 4.4 million households and thousands of businesses lost electricity- caused by the immediate shutdown of 11 nuclear reactors.
  • At Fukushima all 6 of its reactors were so badly damaged that the plant was decommisioned. A 30km evacuation zone was established around the plant and soils in surrounding area were contaminated with radiation. Today, radiation continues to seep into the Pacific ocean- impacting fishing industry.
• Japan experienced several weeks of poer cuts (3-4 hours at a time) which added to economic cost of earthquake. Two oil refineries were also set on fire during the earthquake- one took 10 days to put out.
  
  • 23 train stations were swept away while others suffered damage like collapsed roofs.

Question 6

What were the environmental impacs?

Answer 6

• Fukushima, Japan 2011- Nuclear melt down, nuclear particles found on the west coast of USA- more of an international impact across the North Pacific.
  
  • Unexpected and not prepared for
  • Difficult to stop radiation emitting from this powerstation.
  • The earthquake had knocked out fukushima chamber 1’s power suply to the cooling system of the power plant leading to a nuclear meltdown- overheating.
  • A day later, explosion blew away reactor 1 as a fuel rod heated up and reacted with steam to produce hydrogen gas- this exploding propelling radioactive elements in the atmosphere.
  • This hit two other reactors and radiation levels spike- 100’s of thousands of people living near the plant were evacuated, but the workers who stayed around the plant were most at risk.
  • Seawall 6m high to protect against tsunami- was overtoppled and set of a chain of events- “catastrophic failure of imagination”.
• Tsunami had a larger impact than predicted due to its size but also due to the depression of the land where the flood walls were built, decreasing their height.
  
  • Humans cannot predict natural hazards. Is dependent on context specific factors. They could not have predicted this ground displacement- was why the earthquake had such a large impact.
• Huge impact from the earthquake provoked a 300km stretch rupture in the earths crust from power under the sea.
  
  • Seabed uplift- travelled east across the pacific coast and west to Japan. It occured 24 minutes after the earthquake and in places was 15 metres high
  • Multiple smaller tsunamis along some areas of the coast combined to formone large wave.
  • During earthquake the whole coast dropped by a metre- increasing exposure to vulnerability.
• Land is so flat that the tsunami kept on travelling inland for 10km- hard to escape quickly this far.Same pattern of destruction along 100 miles of coastline.

Question 7

What were the global impacts?

Answer 7

Huge forces from the earthquakes shifted the earths axis up to 25 cm and changed the shape of the planet so that the length of each day is now a tiny bit shorter for the whole world.

Question 8

What were the attempts to mitigate against the event?

Answer 8

• 40% of Japans coastline has a sea wall.
• GPS device every 20km track the movement of underlying plates.
• Land use zoning in 2010 to show the danger zones in the country.
  Catastrophic failure of imagination- no one could have predicted this magnitude of hazards or impacts.

Question 9

What were the attempts to mitigate against vulnerability?

Answer 9

• The majority of the population of japan live along coastal areas due to the restriction and remoteness of mountains inland.
  
  • Increases exposure to threats of tsunamis and flooding- Miayko- 10 metre sea wall failed to hold water back. 60,000 residents failed attempt to mitigate against vulnerability.
• Drainage ditches intended to slow down flow of waterfrom tsunami- water travelled too fast and this was not effective.
• Many houses built of wood easier to be carried away by the tsunami.
• Less than 10 minutes warning for tsunami and 10-20 minutes for earthquake.
• 1995 Earthquake in Kobe was devastated by an earthquake.
  
  • 6000 people were killed- allowed japan to develop much better mitigation strategies in response to these losses.
• Seismic sensors were activated after the warning for the earthquake to shut down 4 nuclear plants, with one of these being Fukushima.
• Coastal people had 20 minutes to evacuate.

Question 10

What were the political impacts?

Answer 10

The japanese government injected billions of money into the economy, especially the financial sector, to bring some stability. This increased government debt at the time when its reduction was a prime political aim.

A large popular movement after the eartrhquake against nuclear power- the current plan is to re-commission a significant number of the currently mothballed nuclear plants.

Political fallout from the nuclear fukushima fallout.